1. Field of the Invention
The invention relates to a vehicle, and particularly relates to a vehicle that includes a rotary electric machine and an inverter for supplying current to the rotary electric machine.
2. Description of Related Art
A technique of suppressing rupture of an oil film is disclosed in Published Japanese Translation of PCT application No. 2008-539682 (JP 2008-539682 A). More specifically, a parameter that indicates a state of an oil film of a bearing for supporting a rotational shaft of a motor is calculated from torque and a rotational fluctuation of the motor. Then, on the basis of the calculated parameter, a rotational speed of the motor is increased to a specified value.
By the way, it has conventionally been known that a phenomenon called electrolytic corrosion occurs to metals around the motor once the motor is driven. The metals around the motor refer to the bearing for supporting the rotational shaft of the motor and the like. The electrolytic corrosion is a phenomenon that metals around a current circuit are corroded by an intermittent flow of stray current, which is leaked from the current circuit to the outside therearound.
In order to suppress occurrence of the electrolytic corrosion, it is desirable to form an insulation oil film on a surface of each metal around the motor and suppress rupture of the oil film. However, in order to suppress the rupture of the oil film and thereby the occurrence of the electrolytic corrosion, if the rotational speed of the motor is increased to the specified value as described in JP 2008-539682 A, output of the motor may be changed, and thus user request output may not be able to be maintained.